Method and apparatus for improving noise discrimination in multiple sensor pairs

Abstract

Noise discrimination in signals from a plurality of sensors is conducted by enhancing the phase difference in the signals such that off-axis pick-up is suppressed while on-axis pick-up is enhanced. Alternatively, attenuation/expansion are applied to the signals in a phase difference dependent manner, consistent with suppression of off-axis pick-up and on-axis enhancement. Nulls between sensitivity lobes are widened, effectively narrowing the sensitivity lobes and improving directionality and noise discrimination.

1. A method for improving noise discrimination in a system having a plurality of sensors each configured to generate an input signal representable by an input vector having a phase component and a magnitude component, the plurality of sensors arranged to have an on-axis direction, the method comprising:
 generating an input electrical signal from each of the plurality of sensors; 
 processing the input electrical signals from the plurality of sensors, said processing including:
 using the input electrical signals from a first pair of sensors to obtain a coarse vector phase difference corresponding to a coarse measurement of an angle of arrival of a signal input source relative to the on-axis direction; 
 using the input electrical signals from a second pair of sensors to obtain a fine vector phase difference corresponding to a fine measurement of the angle of arrival of the signal input source; 
 generating an input phase difference value from the coarse and fine vector phase differences; 
 enhancing the input phase difference value as a function of the angle of arrival to generate an output phase difference value; 
 generating first and second output vectors having a phase difference based on the output phase difference value; and 
 combining the first and second output vectors; and 
 
 generating an output electrical signal based on the combined first and second output vectors. 
 
   
   
     2. The method of  claim 1 , wherein combining comprises summing. 
   
   
     3. The method of  claim 1 , wherein combining comprises differencing. 
   
   
     4. The method of  claim 1 , wherein enhancing is conducted for phase difference values other than 0 degrees. 
   
   
     5. The method of  claim 1 , wherein enhancing is conducted asymmetrically about a selected non-enhancement phase difference angle. 
   
   
     6. The method of  claim 1 , further including applying sensitivity matching to accommodate device and/or signal mismatch in the system. 
   
   
     7. The method of  claim 6 , wherein the sensitivity matching is based on a mathematical mean determination selected from the set of: arithmetic mean, geometric mean, harmonic mean and, a root-mean-square (rms), determinations. 
   
   
     8. A method for improving noise discrimination in a system having a plurality of sensors each configured to generate an input signal representable by an input vector having a phase component and a magnitude component, the plurality of sensors arranged to have an on-axis direction, the method comprising:
 generating an input electrical signal from each of the plurality of sensors; 
 processing the input electrical signals from the plurality of sensors, said processing including:
 using the input electrical signals from a first pair of sensors to obtain a coarse vector phase difference corresponding to a coarse measurement of an angle of arrival of a signal input source relative to the on-axis direction; 
 using the input electrical signals from a second pair of sensors to obtain a fine vector phase difference corresponding to a fine measurement of the angle of arrival of the signal input source; 
 generating an attenuation factor as a function of the coarse and fine vector phase differences; 
 combining the input vectors corresponding the second pair of sensors to obtain output vector; and 
 attenuating the output vector by the attenuation factor; and 
 
 generating an output electrical signal based on the attenuated output vector. 
 
   
   
     9. The method of  claim 8 , wherein combining comprises differencing. 
   
   
     10. The method of  claim 8 , wherein combining comprises summing. 
   
   
     11. The method of  claim 10 , wherein the sensors are arranged in a two-dimension array.